Apparatus for pulling and pressing bearings and the like



Nov. 16, 1965 F. MOBROOM ETAL 3,217,395

APPARATUS FOR PULLING AND PRESSING BEARINGS AND THE LIKE Filed June 29, 1964 3 Sheets-Sheet l Fig. 1.

Fig. 2.

INVENTORS. FREDERRICK M BRooM By and HILTON M BRooM AHarnm 3 Nov. 16, 1965 MOBRQOM ETAL 3,217,395

APPARATUS FOR PULLING AND PRESSING BEARINGS AND THE LIKE Filed June 29, 1964 3 Sheets-Sheet 2 INVENTORS. FR E DE R RICK M BRooM By and HILTON M BRQoM AHarne s Nov. 16, 1965 MOBROOM ETAL 3,217,395

APPARATUS FOR PULLING AND PRESSING BEARINGS AND THE LIKE Filed June 29, 1964 3 Sheets-Sheet 5 INVENTORS.

Fig, 10, FREDERRICK M Bnoom BY ami HILTON M BROOM AHarne s United States Patent 3,217,395 APPARATUS FOR PULLING AND PRESSWG BEARINGS AND THE L Frederrick McBr-oom and Hilton McBroom, Indianapolis,

Ind., assignors to McBrooin Electric Co., Inc., Indianapolis, Ind, a corporation of Indiana Filed June 29, 1964, Ser. No. 378,915 6 Claims. (Cl. 29-252) The present invention relates to an apparatus for pulling and pressing bearings, pulleys, couplings and the like and particularly adapted for working on large electric motors as well as related applications.

In medium and small sized shops where electrical motors are rebuilt and repaired, it is frequently necessary to remove a hearing or coupling or the like from the armature shaft of a large electric motor. In many cases, the bearings have become frozen to the armature shaft so that substantial man hours with hand tools are re quired to remove the bearing. One reason for the problems involved in this work is the difficulty of properly aligning the work in a press or the like whereby force is exerted on the work directly and in an axial direction.

Consequently, one object of the present invention is to provide improved means for removing bearings, pulleys and couplings from electrical motors.

Another object of the present invention is to provide apparatus of the present class incorporating means for centering and positioning a work piece whereby an axial pushing or pulling force or a force in a desired direction can be accurately exerted on the work.

Still another object of the present invention is to provide improved apparatus for pushing or pulling one portion of a work piece relative to another portion thereof.

Related objects and advantages will become apparent as the description proceeds.

One specific embodiment of the invention might include apparatus for pulling and pressing bearings and the like comprising an elongated frame, a plurality of sprockets rotatably mounted on said frame toward one end of said frame and being internally threaded, a first table, a plurality of depending screws fixed to said table and threadedly received within respective ones of said threaded sprockets, an electric drive motor with sprocket mounted on said frame, a closed chain surrounding and meshing with all of said sprockets for raising and lowering said table, a carriage having a pair of V-shaped recesses in the opposite faces thereof, one of said recesses being larger than the other of said recesses for supporting a larger object, rollers rotatably mounted on said carriage at the portions thereof away from the respective V-shaped recesses for portably supporting said carriage with either of said V-shaped recesses up, rails on the upper opposite sides of said table extending longitudinally of said frame and guiding said carriage for longitudinal movement on said table, a further horizontal table fixed to said frame toward the opposite end thereof from said first table, a pair of upright posts mounted on said further table and extending upwardly therefrom centrally of the length of said frame, said upright posts having inwardly opening, mutually facing recesses therein, a pair of pressure plates slidably received in said recesses one above the other, drive means for raising and lowering the lowermost of said pressure plates, a pair of upright rods fixed to said drive means and projecting through both of said pressure plates at the opposite ends thereof and slidably receiving both of said pressure plates, a further carriage having rollers for movement across said further table, four threaded rods extending horizontally above said further table with two of said rods vertically spaced and fixed to one of said posts and the other two of said rods vertically spaced and fixed to the other of said posts, said four rods having their threaded portion extending through said further carriage, four internally threaded sprockets rotatably mounted on said further carriage and threadedly receiving said threaded rods, a second electric motor with sprocket mounted on said further carriage, a chain meshing with and positively coupling all of said further carriage sprockets and said second electric motor sprocket for moving said further carriage relative to said upright posts, and a fluid piston motor mounted on said further carriage and arranged to project said piston toward said pressure plates.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims.

FIG. 1 is a side elevation of an apparatus embodying the present invention.

FIG. 2 is a top plan view of the structure illustrated in FIG. 1.

FIG. 3 is an enlarged vertical section taken along the line 33 of FIG. 1 in the direction of the arrows.

FIG. 4 is an enlarged vertical section taken along the line 4-4 of FIG. 3 in the direction of the arrows and additionally showing certain structure forming a part of the present invention and selectively usable with the structure of FIGS. 13.

FIG. 5 is a horizontal section taken along the line 55 of FIG. 4 in the direction of the arrows.

FIG. 6 is an enlarged vertical section taken along the line 66 of FIG. 3 in the direction of the arrows.

FIG. 7 is an enlarged fragmentary end elevation taken from the right side of the structure :as viewed in FIG. 1 with certain portions broken away to illustrate the internal construction of the apparatus.

FIG. 8 is an enlarged horizontal section taken along the line 88 of FIG. 7 in the direction of the arrows.

FIG. 9 is a horizontal section taken along the line 99 of FIG. 1 in the direction of the arrows.

FIG. 10 is an enlarged vertical section taken along the line 10-10 of FIG. 9 in the direction of the arrows.

FIG. 11 is a fragmentary side elevation of a portion of the structure of FIG. 1 taken as looking from the left of the structure.

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawing and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the in vention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.

Referring more particularly to the drawings, there is illustrated pulling and pressing apparatus 10 which includes a frame 11 incorporating a rectangular tubular portion 12 and transverse angle braces 13 fixed to the tubular portion 12. A vertically adjustable table 15 is mounted on the frame 11 and can be moved upwardly or downwardly by means of a reversible electrical motor 18 fixedly mounted on the cross brace 14 fixed to the upright elements 20 which are, in turn, fixed to the frame 11. The table 15 includes an upper horizontal plate portion 16 from which depends a skirt 17 surrounding the motor 18 and other means described below for vertically adjusting the table.

Referring to FIG. 9, the motor 18 is shown as fixedly mounted on the cross brace 14 and as having operatively coupled thereto a transmission 21 having an output shaft 22 upon which is keyed a sprocket 25. The sprocket 25 drives a chain 26 which surrounds and meshes with a 3 plurality of sprockets 27, a respective one of which is illustrated in FIG. 10.

There are provided four of the upright posts 20 each positioned adjacent a respective corner of the skirt 17. Referring to FIG. which shows a representative one of the posts and associated structure, the posts 20 have a cylindrical shape and at their upper ends each fixedly receives a bearing housing within which is received a roller bearing 31. Each roller bearing 31 rotatably receives and supports a respective one of the sprockets 27.

Adjacent the respective corners of the table 15, there are provided depending screws 32 each of which is threadedly received within a respective one of the sprockets 27. Each of the sprockets 27 is of the same size and has the same number of teeth while each of the screws 32 has the same number of threads per unit length of the screw whereby driving of the chain by the motor 18 causes each screw to be moved vertically the same distance. It can be appreciated that the means for adjusting the vertical position of the table 15 comprising the screws 32, sprockets 27 and chain 26 makes possible raising and lowering of the table 15 in a precisely horizontal attitude throughout the complete range of travel of the table even if heavy weights are resting upon the table and are not centered thereon.

Received for travel across the table 15 and between rails 35 on the opposite sides of the table 15 is a carriage 36 which is particularly adapted for supporting armatures and the like of various sizes. The carriage 36 has a generally square shape as viewed in FIG. 1 and is made up of two closed sections 37 welded to one another at 40 as is best shown in FIG. 11. The carriage 36 has two opposite faces 41 and 42 within which are formed V-shaped recesses 45 and 46 with the recess 45 being substantially deeper and larger than the recess 46. The carriage 36 has two opposite vertically extending sides 47 and 50 upon each of which is rotatably mounted four rollers 51 and 52.

The carriage 36 may be used with the face 41 up and the rollers 51 supported on the table 16. In this position, the carriage and the rollers 51 are guided by the rails 35 which are fixed to the sides of the upper surface of the upper horizontal plate portion 16 as best shown in FIG. 11. Alternatively, the carriage 36 can be inverted from the position illustrated in FIG. 11 so that the carriage is guided and supported by the rollers 52 rolling on the plate portion 16 and limited against transverse movement by the rails 35.

A further table is fixedly mounted on the frame 11 by means of uprights 61 and braces 59. Centrally of the length of the apparatus 10 and at one end of the table 60, there are fixedly mounted upwardly extending posts 62 which have inwardly opening, mutually facing recesses 65 formed therein. The recesses 65 extend vertically and are equally spaced all along their length and receive a pair of pressure plates 66 and 67 which can be slidably moved within the recesses 65 by a reversible electrical motor 70.

The reversible electrical motor 70 is fixedly mounted upon the table 60 and has operatively coupled thereto a transmission 71 which has an output shaft 72 mounting a sprocket 75. The sprocket 75 drives a chain 76 which also meshes with a sprocket 77 (FIG. 6). The sprocket 77 is rotatably mounted within a cage 80 which includes a ball bearing arrangement 81 and a plate 82 fixed in spaced relation to the lower surface of the table 60 by means of screws 85 extending through spacer elements 86 and a top plate 87.

The lowermost pressure plate 66 is formed at its opposite ends with a pair of cylindrical apertures which receive upright cylindrical posts 90 secured to a horizontal member 91. Each of the posts 90 has a reduced size threaded end 92 which joins the main portion of the post 90 by means of a shoulder which is held in firm abutting relation against the upper surface of the horizontal memher 91 by means of the threads of the threaded ends 92. Centrally of the horizontal member 91, there is fixedly secured a screw 95 which is threaded into the sprocket 77. It can be appreciated that rotation of the sprocket by means of the reversible electrical motor 70 either causes a raising or lowering of the screw 95 and also of the pressure plates 66 and 67.

The upper pressure plate 67 is also formed with cylindrical apertures at its opposite ends whereby the pressure plate 67 is slidably received upon the upright post 90. Referring to FIG. 4, it can be seen that the pressure plates 66 and 67 each have a tapered portion and 101 which defines the curved edge 102 and 103, respectively (FIG. 3). The tapered portions 100 and 101 facilitate the placing of the fiat vertically extending forward faces 105 and 106 of the pressure plates directly behind a coupling, hearing or the like to be pressed off of a shaft.

Four threaded rods 110 are fixed to the uprights 62 by means of the threads on the rods which thread into the uprights and by means of nuts 111 on the threads. The rods 110 extend through an upright plate 112 which forms a part of a carriage 115. The carriage 115 also includes a horizontal member 116 fixed to the upright plate 112 and mounting above the horizontal member a hydraulic cylinder motor 117. The horizontal member 116 and the upright plate 112 each mount a pair of rollers 120 upon which the carriage 115 rolls across the table 60. The carriage 115 is propelled across the table 60 by means of a reversible electrical motor 121 having a transmission 122 operatively coupled thereto. The transmission 122 has an output shaft 125 mounting a sprocket 126 which meshes with and drives a chain 130'.

The chain 130 surrounds and meshes with four sprockets 131, the details of which are shown by the representative section FIG. 8. A cup-shaped housing 132 is provided for each of the sprockets 131 and is fixed to the upright plate 112 by suitable screws 135. The cupshaped housing 132 has received therein a ball bearing assembly 136, the inner race 137 of which is fixed to and rotatably mounts the respective sprocket .131. Each of the sprockets 131 is internally threaded whereby the sprockets threadedly receive the horizontal threaded rods 110.

Each of the horizontal threaded rods 110 has the same number of threads per inch as the other horizontal threaded rods and each of the sprockets 131 has the same number of teeth whereby driving of the chain 130 in one direction or the other causes each of the sprockets 131 to rotate the same amount and to move the carriage 115 an equal amount relative to the table 60. Thus, each of the four corners of the upright plate 112 is always moved an equal amount and the upright plate is always maintained in a vertical position throughout the complete range of travel of the carriage 115.

The hydraulic cylinder motor 117 is provided with a piston 140 which may be projected by suitable hydraulic actuating means to force against an object supported by the pressure plates 66 and 67. Referring to FIG. 1, an electrical motor armature 141 is shown supported upon the carriage 36 within the recess 45. The armature 141 has an armature shaft 142 upon which is mounted a coupling 145 found difficult to remove. The present machine may be provided with a plurality of solid metal cylinders 146 of differing diameter and usable for conveying the force from the hydraulic motor piston 140 to the armature shaft 142. The diameter of the cylinder 146 is sufficiently small so that the cylinder can move into the coupling 145 as the pressing operation proceeds. The coupling 145 is supported against'the pressureplates 66 and 67 and more particularly against the flat vertically extending forward faces 105 and 106 of the pressure plates.

In order to maneuver the armature 141 into the illustrated position, the armature may be conveyed to the machine by a suitable overhead crane and then lowered down onto the carriage 36. The carriage can then be adjusted to move the coupling 145 beyond the upright member 62 by pushing the carriage and causing it to roll upon the rollers 51. Next, the table is raised to a point at which the armature shaft 142 is aligned with the piston 140. The lower pressure plate 66 is then raised to a position directly behind the coupling 145 or in other words between the coupling 145 and the armature 141.

The upper pressure plate 67 is then dropped into position by sliding it downwardly on the upright posts 90. Next, the cylinder 146 is held by hand in the proper illustrated position while the reversible motor 121 is operated to move the carriage 115 leftwardly until the piston 140 engages the cylinder 146. It should be mentioned that each of the above mentioned transmissions gears down its respective reversible electrical motor to produce relatively slow but powerful movement of the movable structure. The coupling 145 is then finally removed from the armature shaft 142 by projecting the piston 140 under hydraulic pressure. The hydraulic cylinder motor 117 may be any suitable commercially available hydraulic motor such as, for example, Model No. P-lOO, manufactured by Ener-Pac Div., Blackhawk Industrial Products, Inc. of Butler, Wisconsin.

Referring to FIG. 4, the present apparatus may additionally include an extension 160 which is partially illustrated in FIG. 4. The extension 160 is identical to the pressure plates 66 and 67 and additionally includes a pair of horizontal bars 161 (only one shown). The two bars 161 are used to secure the pressure plate 66 to the pressure plate 66 and to secure an identical pressure plate to the pressure plate 67 in identical fashion. These two additional pressures plates are used in exactly the same manner as the above described manner of use of pressure plates 66 and 67 except for the fact that the additional pressure plates can be positioned leftwardly of the apparatus as viewed in FIG. 1 to accommodate work pieces of different size and shape.

Mounted upon the table 60 is a control board 175 which is provided with push-buttons for moving the various reversible motors in opposite directions. The apparatus is provided with limit switches at various appropriate locations for limiting over-travel of the table 15, carriage 115 and pressure plate 66.

From the above description, it will be evident that the present invention provides an improved means for removing bearings, pulleys and couplings from electrical motors. It should also be emphasized, however, that the present apparatus because of its universal nature can be used in various other applications which require the centering and positioning of a work piece and which also require axial pushing or pulling forces or forces exerted in a desired direction upon a work piece.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention and the scope of the claims are also desired to be protected.

The invention claimed is:

1. Apparatus for pulling and pressing bearings and the like comprising an elongated frame, a plurality of sprockets rotatably mounted on said frame toward one end of said frame and being internally threaded, a first table, a plurality of depending screws fixed to said table and threadedly received within respective ones of said threaded sprockets, an electric drive motor with sprocket mounted on said frame, a closed chain surrounding and meshing with all of said sprockets for raising and lowering said table, a carriage having a pair of V-shaped recesses in the opposite faces thereof, one of said recesses being larger than the other of said recesses for supporting a larger object, rollers rotatably mounted on said carriage at the portions thereof away from the respective V-shaped recesses for portably supporting said carriage with either of said V-shaped recesses up, rails on the upper opposite sides of said table extending longitudinally of said frame and guiding said carriage for longitudinal movement on said table, a further horizontal table fixed to said frame toward the opposite end thereof from said first table, a pair of upright posts mounted on said further table and extending upwardly therefrom centrally of the length of said frame, said upright posts having inwardly opening, mutually facing recesses therein, a pair of pressure plates slidably received in said recesses one above the other, drive means for raising and lowering the lowermost of said pressure plates, a pair of upright rods fixed to said drive means and projecting through both of said pressure plates at the opposite ends thereof and slidably receiving both of said pressure plates, a further carriage having rollers for movement across said further table, four threaded rods extending horizontally above said further table with two of said rods vertically spaced and fixed to one of said posts and the other two of said rods vertically spaced and fixed to the other of said posts, said four rods having their threaded portion extending through said further carriage, four internally threaded sprockets rotatably mounted on said further carriage and threadedly receiving said threaded rods, a second electric motor with sprocket mounted on said further carriage, a chain meshing with and positively coupling all of said further carriage sprockets and said second electric motor sprocket for moving said further carriage relative to said upright posts, and a fluid piston motor mounted on said further carriage and arranged to project said piston toward said pressure plates.

2. The apparatus of claim 1 additionally comprising extension means which includes a further pair of pressure plates, and a pair of horizontally extending members each connecting a respective one of said first mentioned pressure plates to a respective one of said further pressure plates, said last mentioned members each having threaded opposite ends threadedly received in the respective pressure plates and also having enlarged central portions defining shoulders abutting the respective pressure plates.

3. Apparatus for pulling and pressing bearings and the like comprising an elongated frame, a plurality of sprockets rotatably mounted on said frame toward one end of said frame and being internally threaded, a first table, a plurality of depending screws fixed to said table and threadedly received within respective ones of said threaded sprockets, an electric drive motor with sprocket mounted on said frame, a closed chain surrounding and meshing with all of said sprockets for raising and lowering said table, a carriage having a V-shaped recess supporting an object, rollers rotatably mounted on said carriage at the portions thereof away from the V-shaped recess for portably supporting said carriage with said V-shaped recess up, a further horizontal table fixed to said frame toward the opposite end thereof from said first table, a pair of upright posts mounted on said further table and extending upwardly therefrom centrally of the length of said frame, said upright posts having inwardly opening, mutually facing recesses therein, a pair of pressure plates slidably received in said recesses one above the other, drive means for raising and lowering the lowermost of said pressure plates, a pair of upright rods fixed to said drive means and projecting through both of said pressure plates at the opposite ends thereof and slidably receiving both of said pressure plates, a further carriage having rollers for movement across said further table, four threaded rods extending horizontally above said further table with two of said rods vertically spaced and fixed to one of said posts and the other two of said rods vertically spaced and fixed to the other of said posts, said four rods having their threaded portion extending through said further carriage,

four internally threaded sprockets rotatably mounted on said further carriage and threadedly receiving said threaded rods, a second electric motor with sprocket mounted on said further carriage, a chain meshing with and positively coupling all of said further carriage sprockets and said second electric motor sprocket for moving said further carriage relative to said upright posts, and a fluid piston motor mounted on said further carriage and arranged to project said piston toward said pressure plates.

4. Apparatus for pulling and pressing bearings and the like comprising an elongated frame, a plurality of sprockets rotatably mounted on said frame toward one end of said frame and being internally threaded, a first table, a plurality of depending screws fixed to said table and threadedly received within respective ones of said threaded sprockets, an electric drive motor with sprocket mounted on said frame, a closed chain surrounding and meshing with all of said sprocket-s for raising and lowering said table, a further horizontal table fixed to said frame toward the opposite end thereof from said first table, a pair of upright posts mounted on said further table and extending upwardly therefrom centrally of the length of said frame, said upright posts having inwardly opening, mutually facing recesses therein, a pair of pressure plates slidably received in said recesses one above the other, drive means for raising and lowering the lowermost of said pressure plates, a pair of upright rod-s fixed to the opposite ends of said drive means and projecting through both of said pressure plates at the opposite ends thereof and slidably receiving both of said pressure plates, a car riage having rollers for movement across said further table, four threaded rod-s extending horizontally above said further table with two of said rods vertically spaced and fixed to one of said posts and the other two of said rods vertically spaced and fixed to the other of said posts, said four rods having their threaded portion extending through said carriage, four internally threaded sprockets rotatably mounted on said carriage and threadedly receiving said threaded rods, a second electric motor with sprocket mounted on said carriage, a chain meshing with and positively coupling all of said further carriage sprockets and said second electric motor sprocket for moving said further carriage relative to said upright posts, and a fluid piston motor mounted on said further carriage and arranged to project said piston toward said pressure plates,

5. Apparatus for pulling and pressing bearings and the like comprising a frame, a first table mounted for vertical movement on said frame, power means for vertically moving said table relative to said frame, a carriage having a pair of V-shaped recesses in the opposite faces thereof, one of said recesses being larger than the other of said recesses for supporting a larger object, rollers rotatably mounted on said carriage at the portions thereof away from the respective V-shaped recesses for portably supporting said carriage with either of said V-shaped recesses up, rails on the upper opposite sides of said table extending longitudinally of said frame and guiding said carriage for longitudinal movement on said table, a fur ther horizontal table fixed to said frame toward the opposite end thereof from said first table, a pair of upright posts mounted on said further table and extending upwardly therefrom centrally of said frame, said upright posts having inwardly opening, mutually facing recesses therein, a pair of pressure plates slidably received in said recesses one above the other, drive means for raising and lowering the lowermost of said pressure plates, a further carriage having rollers for movement across said further table, four threaded rods extending horizontally above said further table with two of said rods vertically spaced and fixed to one of said posts and the other two of said rods vertically spaced and fixed to the other of said posts, means for moving said further carriage relative to said rods and for firmly fixing said further carriage relative to said rods, and a fluid piston motor mounted on said further carriage and arranged to project said piston toward said pressure plates.

6. Apparatus for pulling and pressing bearings and the like comprising a frame, a first table mounted for vertical movement on said frame, power means for vertically moving said table relative to said frame, a further horizontal table fixed to said frame toward the opposite end thereof from said first table, a pair of upright posts mounted on said further table and extending upwardly therefrom centrally of the length of said frame, said upright posts having inwardly opening, mutually facing recesses therein, a pair of pressure plates slidably received in said recesses one above the other, drive means for raising and lowering the lowermost of said pressure plates, a carriage having rollers for movement across said further table, four threaded rods extending horizontally above said further table with two of said rods vertically spaced and fixed to one of said posts and the other two of said rods vertically spaced and fixed to the other of said posts, means for moving said further carriage relative to said rods and for firmly fixing said further carriage relative to said rods, and a fluid piston motor mounted on said carriage and arranged to project said piston toward said pressure plates.

References Iited by the Examiner UNITED STATES PATENTS 2,390,170 12/1945 Poole 29252 X 3,061,914 11/1962 Johnston 29-234 3,075,346 1/1963 Quarve et a1 29252 X 3,127,024 3/1964 McPherson et al. 29-234 X WILLIAM FELDMAN, Primary Examiner.

MYRON C. KRUSE, Examiner. 

1. APPARATUS FOR PULLING AND PRESSING BEARINGS AND THE LIKE COMPRISING AN ELONGATED FRAME, A PLURALITY OF SPROCKETS ROTATABLY MOUNTED ON SAID FRAME TOWARD ONE END OF SAID FRAME AND BEING INTERNALLY THREADED, A FIRST TABLE, A PLURALITY OF DEPENDING SCREWS FIXED TO SAID TABLE AND THREADEDLY RECEIVED WITHIN RESPECTIVE ONES OF SAID THREADED SPROCKETS, AN ELECTRIC DRIVE MOTOR WITH SPROCKET MOUNTED ON SAID FRAME, A CLOSED CHAIN SURROUNDING AND MESHING WITH ALL OF SAID SPROCKETS FOR RAISING AND LOWERING SAID TABLE, A CARRIAGE HAVING A PAIR OF V-SHAPED RECESSES IN THE OPPOSITE FACES THEREOF, ONE OF SAID RECESSES BEING LARGER THAN THE OTHER OF SAID RECESSES FOR SUPPORITNG A LARGER OBJECT, ROLLERS ROTABLY MOUNTED ON SAID CARRIAGE AT THE PORTIONS THEREOF AWAY FROM THE RESPECTIVE V-SHAPED RECESSES FOR PORTABLY SUPPORTING SAID CARRIAGE WITH EITHER OF SAID V-SHAPED RECESSERS UP, RAILS ON THE UPPER OPPOSITE SIDES OF SAID TABLE EXTENDING LONGITUDINALLY OF SAID FRAME AND GUIDING SAID CARRIAGE FOR LONGITUDINAL MOVEMENT ON SAID TABLE, A FURTHER HORIZONTAL TABLE FIXED TO SAID FRAME TOWARD THE OPPOSITE END THEREOF FROM SAID FIRST TABLE, A PAIR OF UPRIGHT POSTS MOUNTED ON SAID FURTHER TABLE AND EXTENDING UPWARDLY THEREFROM CENTRALLY OF LENGTH OF SAID FRAME, SAID UPRIGHT POSTS HAVING INWARDLY OPENING, MUTUALLY FACING RECESSES THEREIN, A PAIR OF PRESSURE PLATES SLIDABLY RECEIVED IN SAID RECESSES ONE ABOVE THE OTHER, DRIVE MEANS FOR RAISING AND LOWERING THE LOWERMOST OF SAID PRESSURE PLATES, A PAIR OF UPRIGHT RODS FIXED TO SAID DRIVE MEANS AND PROJECTING THROUGH BOTH OF SAID PRESSURE PLATES AT THE OPPOSITE ENDS THEREOF AND SLIDABLY RECEIVING BOTH OF SAID PRESSURE PLATES, A FURTHER CARRIAGE HAVING ROLLERS FOR MOVEMENT ACROSS SAID FURTHER TABLE, FOUR THREADED RODS EXTENDING HORIZONTALLY ABOVE SAID FURTHER TABLE WITH TWO OF SAID RODS VERTICALLY SPACED AND FIXED TO ONE OF SAID POSTS AND THE OTHER TWO OF SAID RODS VERTICALLY SPACED AND FIXED TO THE OTHER OF SAID POSTS, SAID FOUR RODS HAVING THEIR THREADED PORTION EXTENDING THROUGH SAID FURTHER CARRIAGE, FOUR INTERNALLY THREADED SPROCKETS ROTATABLY MOUNTED ON SAID FURTHER CARRIAGE AND THREADEDLY RECEIVING SAID THREADED RODS, A SECOND ELECTRIC MOTOR WITH SPROCKET MOUNTED ON SAID FURTHER CARRAIGE, A CHAIN MESHING WITH AND POSITIVELY COUPLING ALL OF SAID FURTHER CARRIAGE SPROCKETS AND SAID SECOND ELECTRIC MOTOR SPROCKETS FOR MOVING SAID FURTHER CARRAIGE RELATIVE TO SAID UPRIGHT POSTS, AND A FLUID PISTON MOTOR MOUNTED ON SAID FURTHER CARRIAGE AND ARRANGED TO PROJECT SAID PISTON TOWARD SAID PRESSURE PLATES. 